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ACNE GEL FOR GREEN EAR SYNDROME?ASTUDY ON COPPER
CORROSION STAIN REMOVAL FROM POLY (VINYL CHLORIDE)
DawnWallace,AaronShugar,andJonathanThornton
SUNY– BuffaloState,ArtConservationDepartment
TheBarbie™headontherighthasextreme“greenearsyndrome”from
wearingmetalearrings.Below,UVCinducedilluminationdisplaysthe
areaandpenetrationofthestain
SampleMethod
%WeightChange
B1
Stained,Salicylicacid,sun
+0.76
B2
Stained,Salicylicacid
+0.65
B3
Stained,BenzylPeroxide,sun
‐1.21
B4
Stained,BenzylPeroxide
‐1.21
D1
Stained,Salicylicacid,sun
+0.49
D2
Stained,Salicylicacid
+0.77
D3
Stained,BenzylPeroxide,sun
‐1.67
D4
Stained,BenzylPeroxide
‐1.47
Table 1: Sample identification, method of
treatment and % weight changes before and
after test are presented. The salicylic acid had
some gain, possibly due to residue left on the
surface. The benzoyl peroxide showed an
overall decrease in weight indicating loss of
material (B = Barbie, D = Dawn).
The removal of copper corrosion stains within
plasticized poly(vinyl chloride) is of concern to both
conservators and collectors of popular vinyl dolls
such as
Barbie™ and Dawn™.
Where the
conservation field is hesitant to perform intervention
treatments on plastics, public collectors are actively
trying treatment methods that employ acne topical
gels. Two gels, one with salicylic acid and the other
with benzoyl peroxide, were tested according to
these amateur methods to determine their ability to
remove corrosion stains. The results were observed
using normal and fluorescence induced illumination,
and X‐ray fluorescence spectroscopy (XRF).
Four stained samples were taken from both Barbie™
and Dawn™ dolls along with an additional fifth
control sample. Each sample was weighed before
and after treatment. Two of each were tested with
Neutrogena containing 2% salicylic acid and the
other two Clearasil with 10% benzyl peroxide. In
addition, one of the pair was placed in sunlight with
the gel, per suggested public methods. The gel was
applied to half the sample, set over night and then
rinsed with de‐ionized water. This progressed over
20 days, after which all samples were soaked in de‐
ionized water for 24 hours.
B1,salicylicacid,
beforeandafter
Dawn™dollswithgreenstainingattheknees.Thedollshavearticulated
legswithcopperalloymetaljoints,seenbelowinx‐radiograph.
B4,benzylperoxide,
beforeandafter
D2andD3,UVCinduced
fluorescence,beforeandafter
D4,benzylperoxide
beforeandafter
B1 (SA)
B2 (SA)
B3 (BP)
B4 (BP)
D1 (SA)
D2 (SA)
D3 (BP)
D4 (BP)
Comparisonofspectraforbeforeandaftersamples.Onleft,B1before(red)andafter(green).Middle,D1before(red)
andafter(green).Onright,D1swabandsalicylicacidcontrol.
The spectra obtained after treatment for both the Barbie and Dawn samples (left) display
diminished Cu and Zn peaks, and the Dawn samples also have a reduction in Ca. The swab
retained from the D1 sample Day 1 treatment was analyzed and found to contain Cu and Zn. To
exclude contaminants, comparison spectra were obtained from a cotton swab, swab with
salicylic acid, and swab with benzoyl peroxide and found to not contain Cu or Zn.
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Salicylic acid treated samples
displayed nominal visible difference
in normal illumination (top left). The
benzoyl peroxide samples had
diminished stains, but also loss in
material color, a result noted in
amateur use and common from
bleaching agents (top and bottom
right). Sample D4 demonstrates a
change in stain color. In UVA‐induced
illumination the samples had minor
fluorescence, while in UVC, the
salicylic
acid
treatment
had
significant fluorescence, most likely
due to dyes present in the acne gel
(bottom left).
Depth of Cu in PVC
Before m After m
13.7
87.0
13.1
101.6
14.4
53.4
7.3
76.2
3.1
154.9
0.3
137.1
3.5
85.5
0
75.9
Change m
73.3
88.5
38.9
69.0
151.8
136.8
82.0
75.9
To determine the depth of extracted copper, attenuation
calculations were made for copper x‐ray photons travelling
through PVC. Since the copper is not evenly dispersed
throughout the PVC, a theoretical starting point using
spectra with the best α/β ratio of K lines was used (D4) and
the rest normalized accordingly. The data was collected from
area‐under‐peak for the copper K‐lines, and the calculations
determined in microns. The change in m represents the
increased distance copper traveled and thus removal from
the PVC. The salicylic tests show the greatest extraction of
copper, and thus stain.
Further analysis will be done using a scanning electron microscopy (SEM) and mapping the elemental
copper and its migration within the samples. Artificial aging will help predict the long‐term effects on the
PVC samples, such as crazing of the surface, cross‐linking and yellowing. Gas Chromotography‐Mass
Spectroscopy (GC‐MS) be employed on the swabs saved from Day 1 and Day 4 to determine whether
plasticizers were leached from the PVC during treatment.
ACKNOWLEDGEMENTS–TheauthorswouldliketothankJ.J.Chenforherhelpwithimaging,theAndrewW.MellonFoundation,
NationalEndowmentfortheHumanities,andBuffaloStateCollegeTuitionGrantforeducationalfunding.